1. Field of the Invention
The invention relates to a dinitro monomer, a diamine monomer, a polyimide, and a modified polyimide.
2. Description of Related Art
Generally, polyimide (PI) is a polymer material obtained from the polycondensation reaction between a diamine monomer and a dianhydride monomer. Polyimide contains an imide group, and may be divided into aliphatic and aromatic compounds. In terms of aromatic polyimides, aromatic polyimides have good chemical resistance, mechanical property, and thermal stability, and therefore are widely applied to the semiconductor industry, optoelectronics industry, aeronautical materials, biomedical materials, auto industry, communication materials, mechanical industry, and thin film industry. Furthermore, due to the superior electrical property of polyimide, polyimide is utilized in the semiconductor substrates and in packing materials, and has become an integral material in the cutting-edge technology industry.
So far, polyimide still has some problems in processing and preparation. First, since the melting temperature of polyimide is very high, polyimide may not be processed by hot melting. Moreover, the solubility of polyimide in organic solvents is poor, and even some of the aromatic polyimides may only be dissolved in concentrated sulfuric acid. Since the poor solubility is not conductive to the processability of aromatic polyimides, increasing the processability and applicability of aromatic polyimides by preparing a soluble or thermoplastic polyimide is a current issue that those skilled in the art urgently need to solve.